Dynamo electric machine cooling



Aug- 21, 1956 E. BARLOW DYNAMO ELECTRICMACHINE COOLING Filed Nov*l 29, 1954 2 Sheets-Sheet l ,l T. Y It Q \E :1 s Il 1 .I @JT j r /Q4 -Ld Q| I 1 uli -1 1: r. |||l|. .|r n VTLVV A INVENTOR ATTN-NESS Aug. 21, 1956 E. BARLOW DYNAMIC ELECTRIC MACHINE CoCLNC 2 Sheets-Sheet 2 Filed Nov. 29, 1954 NVENTOR ATTORNEYS United States Patent DYNAMo ELECTRIC MACHINE CooLrNG Ernest Barlow, .Sale, England, assignor to Metropolitan- Vickers Electrical Company Limited, London, England, a company of Great Britain Application November 29, 1954, Serial No. 471,8l8

Claims priority, application Great Britain December 4, 1953 4 Claims. (Cl. S10-61) This invention relates to dynamo-electric machines and liras an important application in large size turbo alternaors.

It is well known that one of the main factors limiting the output of a large dynamo-electric machine, such as a turbo alternator, is the rise in temperature, this, in turn, depends upon heat dissipation, the limiting temperature rise being of course the temperature rise of any individual part or component.

It is customary to cool machines by promoting a iiow of gas, such as air or hydrogen, over the surfaces of the core and of the conductors.

The present invention is concerned with improving the cooling of the rotor conductors.

According to the present invention longitudinal passages are formed in the conductors of the winding, at least in the end turn portions of the winding, together with inlet ports extending radially outwards from the interior of the rotor to said passages and discharge ports extending radially outwards from said passages, the inlet and discharge ports being spaced apart along the conductors in such a manner that rotation of the rotor promotes a flow of cooling gas along those parts of the longitudinal passages located between the inlet and discharge ports.

In the case of a coil formed of a number of superimposed conductors each conductor can be formed with a longitudinal passage and inlet and outlet ports may extend radially through all the conductor passages, the inlet ports in such a case extending outwardly only so far as the outermost conductor passage and correspondingly the discharge passages extending inwardly in only so far as the innermost conductor passage, so as to ensure that gas entering through the inlet ports must pass along the conductor passages to the discharge ports.

In order that the invention may be more fully understood reference will now be made to the accompanying drawings, numbered Figs. 1 4 inclusive, which show an arrangement according to the present invention.

In the drawings Fig. l is a plan of an end portion of one rotor winding coil,

Fig. 2 is a cross section of Fig. l along the line AA,

Fig. 3 shows in a plan view a winding comprising three coils arranged one within the other with respect to the rotor periphery,

Fig. 4 shows two alternative cross sections of conductors which may be used in an embodiment of the invention.

Referring to Figs. l and 2 which show one winding coil 1 only, the coil may be formed of a number of superimposed conductors such as 2. Each conductor has a longitudinal passage 3. Inlet ports 4 and discharge ports extend radially through all the conductor passages, the inlet ports in such a case extending outwardly only as far as the outermost conductor passage 6 and correspondingly the discharge ports extending inwardly in only so far as the innermost conductor passage 7, so as to ensure that gas entering through inlet ports 4 must pass along the conductor passages to the discharge ports 5.

2,760,091 Patented Aug. 21, 1956 According to a preferred embodiment of the invention the inlet and discharge ports are formed on opposite sides of each end turn so that the gas circulation will extend along the conductors around the end turns. ln such a case the ports may conveniently be located in the end parts of the slots as shown in Figs. l and 2, the supply to the inlet ports being affected by means of a sub-slot 8 extending from the end of the core beneath the main winding slot 9 whilst the discharge ports may conveniently extend radially outwards through the insulation and winding wedge lil to the periphery of the rotor. Alternatively or in addition, the inlet ports may be formed in the exposed parts 1l of the conductors as shown in Fig. l.

ln the case of a winding comprising a number of coils arranged one within the other with respect to the rotor periphery as shown in Fig. 3, the direction of gas ow in adjacent coils can be arranged to be opposite by suitable positioning of the inlet and discharge ports, the discharge ports 5 being shown in Fig. 3.

The inlet and discharge ports may respectively extend the full length of the slots or alternatively other means of cooling the embedded lengths of the conductors in the slots may be provided.

Referring to Fig. 4, the longitudinal passages 3 in the conductors 2 may be formed by internal grooves 12, i. e., by forming the conductors of a pair of superimposed strips 13 and 14, the abutting faces of which are grooved correspondingly so as to form a duct. Alternatively, a groove or channel l5 may be formed along one face or along both opposite faces of the conductor 2 and may be enclosed by a strip of insulating material 16 extending along the conductor.

it will be appreciated that in some cases additional inlet ports may be distributed around the exposed (i. e., outside the core) end windings.

What l claim as new and desire to secure by Letters Patent of the United States is:

l. A dynamoelectric machine having a stator and a wound rotor, the conductors of the rotor winding containing longitudinal passages at least in the end turns of the winding, means for promoting a iiow of cooling iiuid around said end turns from one side thereof to the other comprising means defining radial inlet ports situated on one side of the end turns and extending outwardly from the center oi the rotor to said longitudinal passages and means defining radial outlet ports situated on the other side of the end turns and extending outwardly from said longitudinal passages to the periphery of the rotor, the arrangement being such that rotation of the rotor causes a pressure difference between said inlet and outlet ports due to centrifugal forces so that cooling fluid flow is promoted therebetween.

2. A dynamo-electric machine having a stator and a wound rotor, the winding coils for the rotor being formed of a plurality of superimposed conductors, said conductors each containing longitudinal passages at least in the end portions of the winding coils, means for promoting a iiow of cooling uid around said end portions from one side thereof to the other comprising means dening radial inlet ports situated on one side of the end portions and extending outwardly from the center of the rotor to the outermost of said longitudinal passages and means defining radial outlet ports situated on the other side of the end portions and extending outwardly from the innermost of said longitudinal passages to the periphery of Athe rotor, the arrangement being suoli that rotation of the rotor causes a pressure difference between said inlet and outlet ports due to centrifugal forces so that cooling fluid flow is promoted therebetween.

3. A dynamo-electric machine having a stator and a wound rotor, the winding coils for the rotor being formed of a plurality of superimposed conductors, said conductors each containing longitudinal passages at least in the end portions of the winding coils, means `for promoting a How of cooling luid around said end portions from one side thereof to the other comprising means defining radial inlet ports situated in the end parts of the rotor winding slots and extending outwardly from the center of the rotor to the outermost of said longitudinal passages7 walls delining sub-slots beneath said rotor winding slots adapted for the supply of cooling Huid and out of which said inlet ports extend, means defining radial outlet ports situated in the end parts of the rotor Winding slots on other side of said end portions to said inlet ports and extending outwardly from the innermost of said longitudinal pas4 sages to the periphery ot the rotor, the arrangement being such that rotation of the rotor causes a pressure difference between said inlet and outlet ports due to ce "ltrifugal forces so that cooling uid ow is promoted therebetween.

4. A dynamo-electric machine having a stator and a wound rotor, the Winding coils for said rotor being formed of a number of superimposed conductors, said conductors each containing longitudinal passages at least in. the end portions of said Winding coils, means for promoting a ow of cooling fluid along said longitudinal passages in said end portions of the winding coils comprising means dening radial inlet ports situated in the end parts of the rotor Winding slots and extending radially inwardly from the outermost of said longitudinal passages, walls dening sub-slots beneath said rotor Winding slots adapted for the supply of cooling uid and into which said inlet ports extend, means detn'mg radial discharge ports situated in the end parts of the rotor winding slots and etending7 radially outwardly from the innermost of said longitudinal passages towards the periphery of the rotor, said inlet and discharge ports being arranged on opposite sides of thc end portion of a Winding coil and with the inlet and discharge pots alternating in adjacent winding coils so that the direction of gas ilow in adjacent coils is opposite.

References Cited in the le of this patent UNTED STATES PATENTS 2,653,255 Baudry Sept. 22, 1953 

